#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>

int main()
{
	char arr1[100] = { 0 };
	char arr2[100] = { 0 };

	scanf("%s", arr1);
	scanf("%s", arr2);

	char* p = arr1;
	char* q = arr2;
	char* ptr = arr2;
	int flag = 1;

	while (*p != '\0')
	{
		q = ptr;

		while (*q != '\0')
		{
			if (*p != *q)
			{
				flag = 1;
			}
			else
			{
				flag = 0;
				break;
			}
			q++;
		}
		if (flag == 1)
		{
			printf("%c", *p);
		}
		p++;
	}
	return 0;
}